EFFECT OF SOME SUBSTANCES ON CONTENT OF SELECTED COMPONENTS IN SOILS CONTAMINATED WITH CHROMIUM

The effect of soil contamination with increasing doses of tri- and hexavalent chromium (0, 25, 50, 100 and 150 mg Cr . kg(-1) of soil) was determined on various properties of soil after cultivation of plants and the neutralizing effect of compost (3 %), zeolite (3 %) and calcium oxide (1 HA) on the contamination. Triand hexavalent chromium in soil, as well as the substances added to it significantly modified its basic physicochemical properties. Contamination of soil with tri- and hexavalent chromium reduced soil acidity and increased total exchangeable base cations, cation exchange capacity and base saturation. Hexavalent chromium had a greater effect on pH and hydrolytic acidity (but not on the total exchangeable base cation or cation exchange capacity) than trivalent forms of the metal. An addition of calcium oxide to the soil effectively neutralized the effect of contamination on the tested properties as it significantly decreased hydrolytic acidity. However, it also reduced total exchangeable base cations and cation exchange capacity only with chromium(III) as compared with the control series (with no additives). The effect of the other substances was weaker and more positive in the case of compost than zeolite, especially in the objects with hexavalent chromium.